Apparatus for the manufacture of pig iron



Dec. 4, 1928. 1,693,916

G. DE BETHUNE APPARATUS FOR THE MANUFACTURE OF PIG IRON Filed July 15, 1925 Patented Dec. 4, 1928.

"UNITED STATES GASTON DE IBETHUNE, OF BRUSSELS, BELGIUM.

APPARATUS FOR THE MANUFACTURE or PIG .rnon.

Application filed July 15, 1925, Serial No. 43,854, and in Belgium March 5, 1925.

The subjectof this invention is the introduction, intofurnaces or blast furnaces whlch' they are working, of materials or residues of various kinds which either increase the production of pig iron or modify the working of the said furnaces or blast furnaces.

The introduction, according to the method claimed by the invention, of these materials, the nature of which mayvary according to the case and which are previously'crushed or pulverized, enables in particular the basicity of the slags and the internal temperaturesof the furnace to be increased or decreased rapidly, and the composition of the gases produced by the latter to be varied. In the case where the materials introduced are ores or the residues of ores, the method according to the invention enables the, output of the furnace to be increased, use being made of ma- 2 terials whichare generally thrown away in spite of their value.

Th'e present invention relates to apparatus serving for the introduction, especially into blast furnaces or the like of comminuted materialeither pulverized or otherwise, and in cluding a plurality of tuyeres disposed coaxially one within the other from one or more of which a jet of air under pressure is delivered, assuring the entrainment and injection of the material to be introduced into the furnace. V

The utilization of unheated air under pressure presents the inconvenience on the one hand of unduly cooling theinterior of the blast furnace and producing in consequence, divers derangements in the operation of the furnace or the character of the product,.and on the other hand, through the humidity of the unheated air,producing the adherence of material to the tuyeres, partially or wholly occluding them, unless the, unheated air has been previously dessicated.

It may be observed on the other hand, that if the air is heated, its density is too slight to 5 assure suflicient velocity for the proper entrainment of the material, unless the air is injected in such great quantity as to consid erably accelerate combustion within the furnace, under which conditions it follows that the pressure of the furnace is augmented to such an extent as to diminish yet further, the efficiency of the current of heated air as a vehicle for the'introduction of the comminuted material. u The invention consequently has for its objectthe utilization of the advantages resulting from the employment both of heated air and of unheated air, and in avoiding at all times the disadvantages of. each when used separately.

make use of heated air in order to improve theoutput of the furnace and to avoid the accumulation of material in the tu'yeres which is never produced under heated air conditions,

and to utilize equally, a certain proportion of unheated air under relatively high pressure to assure the entrainment of the material.

- This purpose is realized following theprinciples of the invention, by means of an apparatus including a tuyere having two cylindrical portions of different diameters ea ch terminating in a nozzle having the shape of j a conical portion terminating in a cylindrical portion of small diameter, the walls of which are cooled by circulation of water, it being understood that the jet of heated air envelops the jet of unheated air so as to sub stantially keep the latter out of contact with the walls of the tuyeres, thereby avoiding the chilling of said walls and the depositing thereupon of condensed matter.

The advantages and characteristics of the invention are set forth in the following description of the sole figure which represents in cross section a tuyere' with the associated injectors embodying the principles of the invention.

' Referring now in detail to the figure, the apparatus consists of a tuyere 1 with hollow walls in which circulates water, with inlet and outlet pipes 2 and 3 above which opens out a channel 4 which admits the materials which are to be introduced in the form of dust the delivery through this duct 4 is regulated'by a suitable valve 5; the inner wall of the said tuyere is also protected by a removable part 6.

In order that the materials fed in the tuyere'l will be carried along, hot draii' ht and compressed air in ectors are provide (so With thisend in View it is contemplated to tioned injector is placed a second injector 10 with aconical lllOLlt-ll-PlQCG, through which is delivered the compressed air passing through a pipe provided with a suitable valve l2. Manon eters are providedton the co npressed air plpeg the hot draught pipe and also on the tuyere 1 so as to indicate th-evalue .of'the pressures andpartialvacuums produced in these pipes... n

It Willbe seen that it is possible to modify the introduction of the materials in a perfect manner by regulating the valves;5,;9 a nd'12 and that in certain cases the apparatusmay serve for introducing either a hot draught andcompressed air or if desiredgases under pressure; similarly, Tthe materials carried along niay inlcerjtain cases only consist of either fuel, or a fuel mixed with certain melting nesia" and thenliket WhatJI claimis:

,1; Apparatus for theintroduction into furnaces of coinminuted material, comprising a v a-terials such as limes, sand, 1nagtuyere including two cylindrical portions of dlflerent diameters having anihterinediate tapering portion, a channel delivering the "material to the cylindrical portion of greater diameter, an injector delivering heated air to the interior of said tuyere below said channel, a seeendinjeetor disposed coaxially on theinteriorol the first and delivering unheated airunder pressure; the second cylindrical portiondeliveringmaterial. to the in terior of thelfurnaee havingrelatively great length and relatively small cross Jetion and including means for eooliiigth'e W'a ls tliereof.

2. Apparatus for the in qduction'into furnacesfof coinininntedmaterial, comprising a tnyere includingm cylindrical portions of dill'erent diameters having an intenne dt 'e tapering portion, a cl itnn'el delivering the} terial into the cylindrical portionof greater.

diameter, 1 and an injector "delivering heated air to saidtuyfre below said channel, a second injector d sposed =coaxially off the111terior o'l':

the first injector,anddeliverin I unheated f a-i r under! pressure, the second ,0

jinn-ital p rof the furnace 2 having s a relativelygrelit length and relatively smalljc'ross section, the walls bein cooledbythe ci'rculationofLwater. In testimony whereof ljhavle s i nedgniy name to thisspecificationi J (GASTON H HWE 55 ,tion delivering the n aterialto the; interior 

